NO. 1458. CA.Af BRIAN FAUNAS OF CHINA— WALCOTT. 575 



upper portion; the furrows divide the axis into five segments, or 

 rings, and the subtriangular terminal portion, that slopes rapidly from 

 its center to the thickened border; lateral lobes broad, convex, and 

 marked by a narrow, anterior, elevated segment, which joins the 

 thorax, and three strong, narrow, elevated ridges, and a small node 

 terminating a fourth ridge; the ridges are separated by broad, strong 

 furrows that are continuations of the furrows crossing the axis; the 

 thickened border is separated from the body of the pygidium by a 

 shallow groove; from the border there are backward extending spines 

 on each side of the central axis, the second of which, on each side of 

 the axis, is longer and stronger than the others. 



Surface of the crust of the head, free cheeks, and pygidium, and 

 associated fragments of the segments of the thorax minutely punctate. 

 The largest head in the collection has a length of 20 mm., with the 

 same width at the palpebral lobes; the largest pj^gidium has a width 

 of 35 mm. and a length of 18 mm., exclusive of the spines. 



Observations. — The character of the frontal limb and rim of this 

 species is quite like that of the tj'pe of the genus, jBlachoelderias wen- 

 sis Bergeron." There is a difference in the surface, as there are no 

 tubercles known on the surface of B. cllix.^ On account of the gen- 

 eral resemblance between the heads and p3^gidia of the genera Dames- 

 ella and Blackioelderia we may compare species of the two genera. 

 We find in B. sinensis Bergeron a form of head and surface somewhat 

 intermediate between Damesella hlachwelderi^ and B. cilix. The sur- 

 face of B. sinensis is minutely punctate like that of B. cilix, and in 

 addition it has scattered pustules of the character of those so thickl}^ 

 dispersed over the surface of D. hlackwelderi. The frontal limb of 

 B. sinensis is somew^hat intermediate in form between that of B. cilix 

 and D. Jjlachpelderi. If the border of B. sinensis were a little more 

 thickened we should have the appearance of the frontal rim or border 

 of I), hlachvelderi. One of the specimens of B. sinensis has a frontal 

 limb and border somewhat like that of B. cilix. 



The form of the glabella of B. cilix is similar to that of B. sinensis 

 Bergeron, but the frontal limb is much broader than in that species, 

 the lixed cheeks narrower and less elevated, and the surface is appar- 

 ently without granulations. 



FoTination and loccdity. — Middle Cambrian, in a concretionary, 

 ocherous limestone that may correspond to the Ku-shan shale horizon 

 of the Shan-tung sections; 4 miles east of Fang-lan-chon, Shan-si, 

 China. 



Collected by Eliot Blackwelder. 



c- Calymmene f sinensis Bebgeron, 1899, Bull, de la Soc. G^ol. de France, 3rd ser., 

 XXVII, p. 500. 



bOlenoidesf cilix WAlcott, 1905, Proc. U. S. Nat. Mus., XXIX, p. 27. 

 cVroc. U. S. Nat. Mus., XXIX, 1905, p. 35. 



